1. FIELD OF THE INVENTION
The present invention relates to a protection device for highway workers and more particularly to a warning device for alerting highway workers of oncoming vehicles which have strayed toward the work zone.
2. DESCRIPTION OF THE PRIOR ART
The number of highway work zone related fatalities has nearly doubled in the last ten years. In 1991, there were approximately 25,000 disabling injuries in work zones. In 1993, according to the National Highway Transportation Safety Administration, there were 762 work zone fatalities on United States roadways. The Occupational Safety and Health Administration reports that 59% of highway workers killed are struck by motorists mistakenly entering work zones. Numerous safety devices have been developed to prevent accidents between highway workers and errant vehicles. Examples include the method of protecting a roadway maintenance and construction site disclosed in U.S. Pat. No. 4,600,178 issued Jul. 15, 1986, to S. Zucker et al. and the apparatus for road repair work including a protective cage disclosed in U.S. Pat. No. 4,636,111 issued Jan. 13, 1987, to J. V. Joyce. Such barriers prevent errant vehicles from entering a limited area of a roadway. For larger temporary work zones it is not always possible to erect barriers to keep vehicles from entering all parts of a work zone. Non-barrier devices have been developed to warn drivers of road hazards such as construction work zones. World patent application No. WO 87/00326 published Jan. 15, 1987, shows such a warning signal. U.S. Pat. No. 3,880,537 issued Apr. 29, 1975, to F. C. Harris et al. discloses another road hazard warning device. These devices rely on warning the driver of the vehicle to prevent accidents. However, vehicles continue to mistakenly enter highway work zones despite the existence of such warning devices. It is therefore advantageous to provide highway workers warning of oncoming errant vehicles in time to take evasive action. U.S. Pat. No. 5,265,556 issued Nov. 30, 1993, to J. R. Hall shows such a device. The Hall device consists of a traffic control barrier which if knocked over by an oncoming vehicle emits a loud audible alarm. The Hall device warns workers of errant vehicles entering the workzone at a single location and is useful for a single occurrence. A highway signal device which may detect vehicles over a larger area is shown in U.S. Pat. No. 2,966,877 issued Mar. 29, 1957, to W. G. Konold et al. The mechanical actuator of Konold limits the maximum length of the pneumatic tube and requires the signal device to be mechanically connected to the pneumatic tube. Electrical pressure switches connected to pneumatic tubing are shown in U.S. Pat. No. 5,406,258 issued Apr. 11, 1995, to D. W. Carver. The security barrier of Carver relies on the release of pressure due toga rupture of the tubes of the device to actuate an alarm.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.